One of the key challenges facing modern industrialized society is the rapid depletion of crude oil, which is the primary source for most transportation fuels and many organic chemicals. The petrochemical industry represents a substantial benefit to human society and the invention and commercialization of alternative sources for petrochemicals is of great importance.
One category of organic chemicals that is often produced from petroleum includes aromatics. These chemicals have a wide range of uses including serving as monomers for many types of polymers, paints, and coatings; serving as chemical intermediates for many types of industrial and consumer chemicals; and serving as valuable chemical components of heterogeneous transportation fuels such as gasoline, diesel, aviation gasoline, and jet fuel.
Surprisingly, very little work has been done to develop a method of producing aromatics from renewable sources. Gruber et al. (U.S. Patent Application Publication No. 2009/0299109) describe a method for producing aromatic compounds from cellulosic/hemi-cellulosic/lignin biomass. According to Gruber's method, cellulosic/hemi-cellulosic/lignin biomass is subjected to fermentation with one or more micro-organisms to form one or more C2-C6 alcohols. The alcohols are converted into C2-C6 alkenes by dehydration and then isolated from other compounds. These C2-C6 alkenes are then catalytically reacted to form one or more aromatic hydrocarbons. To date, the only method based on the fermentation of cellulosic/hemi-cellulosic/lignin biomass to alcohols that has been commercialized involves the production of ethanol as a substitute for motor gasoline. Concerns with fermentation through alcohol pathways are the high consumption of water and low overall energy efficiency [Doherty, W. O. S., Mousavioun, P., Fellows, C. M., Value-adding to cellulosic ethanol: Lignin polymers, Industrial Crops and Products, Volume 33, Issue 2, March 2011, Pages 259-276., A. Széchényi, R. Barthos, and F. Solymosi, Aromatization of ethanol on Mo2C/ZSM catalysts, Catalysis Letters Vol. 110, Nos. 1-2, August 2006]. Thus, a need exists to provide an alternative pathway that can provide a source for aromatic chemicals so that demand can be satisfied as the available supply of source material, i.e., crude oil, is depleted while addressing concerns with fermentation through alcohol pathways.
During the scale-up of a process to noncatalytically crack fatty acid based oils including but not limited to crop oils and other triacyl glycerides; fatty acid lipids produced by microbes, fungi, and yeasts; and animal fats, in a continuous reaction system, an unusual cracking reaction product was obtained that has not been documented in previous literature nor was seen during previous batch reaction experiments. This cracking reaction product contains a high concentration of C2-C16 alkenes. This unusual result, coupled with subsequent catalytic reforming of these alpha alkenes, is the basis of a new process to generate renewable aromatics from fatty acid oils.